Org reader: respect export option for tags

Tags are appended to headlines by default, but will be omitted when the
`tags` export option is set to nil.

Closes: #3713

src/Text/Pandoc/Readers/Org/DocumentTree.hs

@@ -220,12 +220,16 @@ headlineToHeaderWithContents hdln@(Headline {..}) = do
 headlineToHeader :: Monad m => Headline -> OrgParser m Blocks
 headlineToHeader (Headline {..}) = do
   exportTodoKeyword <- getExportSetting exportWithTodoKeywords
+  exportTags        <- getExportSetting exportWithTags
   let todoText    = if exportTodoKeyword
                     then case headlineTodoMarker of
                       Just kw -> todoKeywordToInlines kw <> B.space
                       Nothing -> mempty
                     else mempty
-  let text        = todoText <> headlineText <> tagsToInlines headlineTags
+  let text        = todoText <> headlineText <>
+                    if exportTags
+                    then tagsToInlines headlineTags
+                    else mempty
   let propAttr    = propertiesToAttr headlineProperties
   attr           <- registerHeader propAttr headlineText
   return $ B.headerWith attr headlineLevel text

src/Text/Pandoc/Readers/Org/ExportSettings.hs

@@ -71,7 +71,7 @@ exportSetting = choice
   , ignoredSetting "pri"
   , ignoredSetting "prop"
   , ignoredSetting "stat"
-  , ignoredSetting "tags"
+  , booleanSetting "tags" (\val es -> es { exportWithTags = val })
   , ignoredSetting "tasks"
   , ignoredSetting "tex"
   , ignoredSetting "timestamp"

src/Text/Pandoc/Readers/Org/ParserState.hs

@@ -240,6 +240,7 @@ data ExportSettings = ExportSettings
   , exportWithAuthor       :: Bool -- ^ Include author in final meta-data
   , exportWithCreator      :: Bool -- ^ Include creator in final meta-data
   , exportWithEmail        :: Bool -- ^ Include email in final meta-data
+  , exportWithTags         :: Bool -- ^ Keep tags as part of headlines
   , exportWithTodoKeywords :: Bool -- ^ Keep TODO keywords in headers
   }
 
@@ -258,5 +259,6 @@ defaultExportSettings = ExportSettings
   , exportWithAuthor = True
   , exportWithCreator = True
   , exportWithEmail = True
+  , exportWithTags = True
   , exportWithTodoKeywords = True
   }

test/Tests/Readers/Org.hs

@@ -794,6 +794,12 @@ tests =
                       , "** DONE todo export"
                       ] =?>
               headerWith ("todo-export", [], []) 2 "todo export"
+
+          , "remove tags from headlines" =:
+              unlines [ "#+OPTIONS: tags:nil"
+                      , "* Headline :hello:world:"
+                      ] =?>
+              headerWith ("headline", [], mempty) 1 "Headline"
           ]
       ]